U.S. patent number 5,623,876 [Application Number 08/518,612] was granted by the patent office on 1997-04-29 for apparatus and method for positioning a printing mechanism between stations in a mail handling apparatus.
This patent grant is currently assigned to Pitney Bowes Inc.. Invention is credited to Charles F. Murphy, III, Patrick Murphy.
United States Patent |
5,623,876 |
Murphy, III , et
al. |
April 29, 1997 |
Apparatus and method for positioning a printing mechanism between
stations in a mail handling apparatus
Abstract
A mail handling apparatus having a printing mechanism; a device
for moving the printing mechanism along a path of travel between a
printing mechanism printing position and a printing mechanism
maintenance position; a maintenance station positioned lateral to
the path of travel; and a device for rotating the printing
mechanism along the path of travel to align the printing mechanism
for engagement with the maintenance station as the printing
mechanism moves into the maintenance position.
Inventors: |
Murphy, III; Charles F.
(Milford, CT), Murphy; Patrick (Stamford, CT) |
Assignee: |
Pitney Bowes Inc. (Stamford,
CT)
|
Family
ID: |
24064709 |
Appl.
No.: |
08/518,612 |
Filed: |
August 23, 1995 |
Current U.S.
Class: |
101/483; 101/425;
347/33; 400/702 |
Current CPC
Class: |
B41J
2/16538 (20130101) |
Current International
Class: |
B41J
2/165 (20060101); B41J 002/165 () |
Field of
Search: |
;400/320,320.1,328,29,30,31,143,142,140,701-702 ;101/45,483,425
;347/33 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Eickholt; Eugene H.
Attorney, Agent or Firm: Shapiro; Steven J. Scolnick; Melvin
J.
Claims
What is claimed is:
1. A mail handling apparatus comprising:
a carriage assembly;
a digital printing mechanism having a plurality of printing nozzles
and being rotatably connected to the carriage assembly;
means for moving the carriage assembly along a path of travel
between a printing mechanism printing position and a printing
mechanism maintenance position;
a maintenance station having a wiper blade and being positioned
lateral to the path of travel; and
means for rotating the printing mechanism out of the path of travel
to align the printing nozzles of the printing mechanism
substantially parallel to the wiper blade for engagement with the
wiper blade as the carriage assembly moves into the maintenance
position.
2. A mail handling apparatus as set forth in claim 1, wherein the
mail handling apparatus includes a feed path along which mailpieces
are processed through the mail handling apparatus, the feed path
being transverse to the path of travel and the printing mechanism
being located along the feed path in the printing position.
3. A mail handling apparatus comprising:
a printing mechanism;
means for moving the printing mechanism along a path of travel
between a printing mechanism printing position and a printing
mechanism maintenance position;
a maintenance station positioned lateral to the path of travel;
and
means for rotating the printing mechanism for engagement with the
maintenance station as the printing mechanism moves into the
maintenance position;
wherein the moving means comprises a moveable carriage assembly
having the printing mechanism operatively connected to the carriage
assembly to move therewith, a motor and a lead screw, and wherein
the lead screw is connected to the motor and is driven into
rotation by the motor and the carriage assembly is mounted on the
lead screw such that at times when the motor drives the lead screw
into rotation a corresponding movement of the carriage assembly
along the lead screw occurs.
4. A mail handling apparatus as set forth in claim 3, wherein the
rotating means comprises a shaft rotatably disposed in the carriage
assembly and fixedly connected to the printing mechanism, a first
gear fixedly connected to the shaft to rotate therewith, and a
second gear located to intermesh with the first gear during at
least a portion of movement of the carriage assembly along the lead
screw, and wherein at times when the first and second gears
intermesh the shaft is forced into rotation causing a corresponding
rotation of the printing mechanism.
5. A mail handling apparatus as set forth in claim 4, wherein the
carriage assembly comprises a main platform and a secondary
platform, and wherein the main platform is mounted on the lead
screw, the printing mechanism is fixedly mounted on the secondary
platform, and the secondary platform is mounted on the shaft to
rotate therewith.
6. A mail handling apparatus as set forth in claim 5, wherein the
secondary platform has a spring loaded pin mounted thereon and the
main platform has first and second detents, at times when the
printing mechanism is in the printing position the spring loaded
pin is disposed in the first detent securing the printing
mechanism, at times when the printing mechanism is in the
maintenance position the spring loaded pin is in the second detent,
and at times when the printing mechanism moves along the path of
travel such that the first and second gears intermesh the secondary
platform rotates with the shaft causing a corresponding movement of
the spring loaded pin between the first and second detents.
7. A mail handling apparatus as recited in claim 6, further
comprising a lever arm pivotally mounted to the secondary platform,
means for biasing the lever arm away from the secondary platform,
and means for moving the lever arm against the biasing force of the
biasing means and into contact with the spring biased pin during
movement of the carriage assembly along the lead screw such that
the lever secures the spring biased pin within the second detent
prior to engagement of the printing mechanism with the maintenance
station.
8. A method for positioning in a mail handling apparatus a carriage
assembly having rotatably mounted thereon a digital printing
mechanism with a plurality of nozzles, the method comprising the
steps of:
moving the carriage assembly along a path of travel between a
printing mechanism printing position and a printing mechanism
maintenance position;
rotating the printing mechanism out of the path of travel to align
the printing mechanism substantially parallel to a wiper blade of a
maintenance station for engaging the nozzles with the wiper blade
as the printing mechanism moves into the maintenance position, the
maintenance station being positioned lateral to the path of
travel.
9. A method as set forth in claim 8, wherein the path of travel is
transverse to a feed path of the mail handling apparatus over which
mailpieces are processed and the printing mechanism is located in
the feed path in the printing position.
Description
BACKGROUND
This invention relates to an apparatus and method for positioning a
printing mechanism, and more particularly to a printing mechanism
for positioning a printing mechanism between printing and
maintenance stations in a mail handling apparatus.
Mail handling machines, such as that described in U.S. Pat. No.
4,935,078 process mixed mailpieces (varying size) in a high speed
manner. These known mail handling machines typically include a
front end feeder, a singulator, a moistener, a sealer, and a
printing device. The front end feeder shingles the incoming
mailpieces (such as envelopes) and the singulator grabs the bottom
envelope from the shingled stack of envelopes for subsequent
processing downstream. Upon passing by the singulator, the envelope
is successively fed past the moistener where its flap portion is
moistened and is then passed through a sealer where the flap is
sealed prior to the printing of, for example, postage values
thereon by the printing device (postage meter). Moreover, the mail
handling machine may further include a scale for weighing the
mailpieces and a tape mechanism for printing of indicia on a
tape.
Modern mail handling machines utilize digital printing techniques
for producing images on a mailpiece being processed therethrough.
Conventional digital printing techniques include bubble jet,
piezoelectric ink jet, and thermal ink transfer which each produce
an image in a dot matrix pattern. That is, in digital ink jet
printing individual printhead elements (such as resistors or
piezoelectric elements) are selectively electronically stimulated
to expel drops of ink from a reservoir onto a substrate. In the
case of thermal ink transfer, individual resistive elements which
contact a thermal inking transfer tape are selectively energized to
transfer ink from the tape on to a substrate in contact with the
tape. In either case, by controlling the energizing timing of the
individual printhead elements in conjunction with the relative
movement between the printhead and the mailpiece, a dot matrix
pattern is produced in the visual form of the desired indicia.
Digital printing technology has significant advantages when used in
a mail handling apparatus as compared to older technology which
utilized either a flat platen or a rotary drum to imprint indicia
on mailpieces. For example, if the variable indicia image data
needs to be changed, it can easily be done through the installation
of new or upgraded software versus having to replace the entire
meter since the flat platen and drum do no get removed. Moreover,
greater printing speeds can be obtained as compared to conventional
mechanical printing systems. However, the use of a digital
printhead in a mail handling apparatus presents special maintenance
requirements which must be undertaken in order to ensure that the
printhead continues to perform satisfactorily. That is, since the
size of the nozzle openings in the printhead through which the
individual drops of ink are expelled are very small, they can
easily become clogged by debris or dried ink. If this occurs, the
clogged nozzle will not be able to have ink expelled therethrough.
Eventually, if enough nozzles become clogged, the indicia image
produced will degrade to an unacceptable level. Accordingly, it is
very important to keep the printhead nozzles free of any
contamination when the printhead is not printing.
Typically, office apparatus having digital printheads have a
maintenance station located at one end of the direction of travel
of the printhead. The maintenance station includes a printhead
cover which is designed to cover and hermetically seal the
printhead nozzles as the printhead moves into a maintenance (home)
position. The hermetic seal helps to prevent the ink from drying in
the nozzles and provides a shield from contamination while not
printing. Moreover, the maintenance station typically has wipers
associated therewith which wipe the nozzles just prior to or after
their being covered by the printhead cover. The wipers remove any
contamination that may have been deposited on the nozzles during
printing or ink accumulated during maintenance. Additional
maintenance features which may be associated with the maintenance
station include the ability to provide a vacuum burst to the
nozzles to unclog clogged nozzles and a purge capability for
clearing the nozzles.
As previously mentioned, conventional office apparatus typically
move their printheads back and forth along a single path of travel.
The maintenance station is often located at the one end of the path
of travel in the home position such that after a printing operation
the printhead returns to the home position where it is serviced by
the maintenance station. However, in a mail handling apparatus the
front end feeder, singulator, moistener, sealer, printing station,
and stacker are typically aligned one after the other in the
direction of travel of the mailpiece through the mail handling
apparatus. This creates a mail handling apparatus with a long
footprint. Accordingly, if a maintenance station for a digital
printhead is placed in line with the flow of mail, it will add to
the overall length of the machine. Additionally, since the
maintenance station is situated within the mail flow, it is very
vulnerable to collecting paper dust associated with the mailpieces.
Thus, the printhead cover could collect paper dust therein which,
in turn, could clog the printhead nozzles when the printhead is
protected by the cover.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a mail handling
apparatus having a digital printhead which is easily moveable
between a print position in line with the flow of mail and a
maintenance station that is not situated within the flow of mail,
to minimize the footprint of the mail handling apparatus and
position the maintenance station away from the flow of mailpieces
through the mail handling apparatus. This object is met by a mail
handling apparatus having a printing mechanism; means for moving
the printing mechanism along a path of travel between a printing
mechanism printing position and a printing mechanism maintenance
position; a maintenance station positioned lateral to the path of
travel; and means for rotating the printing mechanism along the
path of travel to align the printing mechanism for engagement with
the maintenance station as the printing mechanism moves into the
maintenance position.
A further object of the invention is to provide a method for
positioning a printing mechanism within a mail handling machine
between a printing position and a maintenance station. The method
including the steps of moving the printing mechanism along a path
of travel between a printing mechanism printing position and a
printing mechanism maintenance position; rotating the printing
mechanism along the path of travel to align the printing mechanism
for engaging the printing mechanism with a maintenance station as
the printing mechanism moves into the maintenance position, the
maintenance station being positioned lateral to the path of
travel.
Additional objects and advantages of the invention will be set
forth in the description which follows, and in part will be obvious
from the description, or may be learned by practice of the
invention. The objects and advantages of the invention may be
realized and obtained by means of the instrumentalities and
combinations particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of the inventive mail handling apparatus
showing the printhead in the mailpiece printing position;
FIG. 2 is a top plan view of FIG. 1;
FIG. 3 is a right side view of FIG. 1;
FIG. 4 is a top plan view of the mail handling apparatus showing
the printhead in the maintenance position; and
FIG. 5 is a left side view of FIG. 1 showing the top registration
structure.
The accompanying drawings, which are incorporated in and constitute
a part of the specification, illustrate a presently preferred
embodiment of the invention, and together with the general
description given above and the detailed description of the
preferred embodiment given below, serve to explain the principles
of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1-5, the inventive printhead positioning
apparatus is shown incorporated within a mail handling machine 1
(only portions of which are shown). In FIGS. 1 and 2, a printhead 3
is shown in solid lines in a tape printing position and in dashed
lines in a mailpiece printing position. Specifically, FIG. 1 shows
a front view of the mail handling apparatus 1 looking directly
opposite to the flow of a mailpiece 5 through the mail handling
apparatus 1. Mailpiece 5 is transported at a constant speed and in
a conventional manner past the mailpiece printing position via the
interaction of a driven belt 7 and an idler pulley 9 which is
biased upwardly by springs 10. Pulley 9 is mounted to a plate
structure 11 which in turn is mounted to a housing (not shown) of
mail handling apparatus 1. A registration plate 13 of plate
structure 11 includes an opening 15 therein through which ink from
each of printhead nozzles 17 pass for deposit on mailpiece 5.
Referring to FIG. 5, a top registration structure is identified at
20. Structure 20 includes a curved plate 20a hingedly connected in
a conventional manner at 20b and biased to rotate counterclockwise
toward the bottom of registration plate 13 due to the biasing force
of spring 20c which is connected between curved plate 20a and a
stationary ground portion 20d. A top portion 20aa of plate 20a is
wider than opening 15 so that it does not pass through opening 15.
Thus, as mailpiece 5 enters the nip between top portion 20aa and
the bottom of registration plate 13, plate 20a is forced to rotate
in the clockwise direction of FIG. 5. Spring 20a however maintains
a biasing force on plate 20a which keeps mailpiece 3 registered
against the bottom surface of registration plate 13 thereby fixing
the distance between the nozzles 17 and the top surface 18 of
mailpiece 5. The fixed distance is necessary to ensure that an
acceptable print quality is achieved. As the mailpiece 5 passes by
printhead 3, nozzles 17 are energized in synchronism with the
relative movement between printhead 3 and mailpiece 5 in a
conventional manner to produce the desired image on the top surface
18 of mailpiece 5.
A tape print station 19 is shown schematically. Tape print station
19 provides a piece of tape 21 below printhead 3 for printing
thereon. The structure of tape print station 19 is well known in
the art and no further description is considered necessary for the
purpose of describing the invention claimed herein. Moreover, a
registration structure to similar to that set forth above in
connection with mailpiece 5 can be incorporated to ensure proper
registration of tape 21 relative to nozzles 17.
Printhead 3 is attached to a printhead carriage assembly 23.
Carriage assembly 23 includes a main platform 25 having a lower
boss portion 25a and upper boss portion 25b. A shaft 27, having a
gear segment 29 fixedly connected to one end thereof, is rotatably
mounted within main platform 25, lower boss 25a, and upper boss
25b. A secondary platform 31 is fixedly connected to shaft 27 at
the end opposite from gear segment 29. Thus, as shaft 27 rotates,
gear segment 29 and secondary platform 31 will rotate therewith.
Secondary platform 31 further includes a pair of L-shaped extending
arms 31a and 31b which are attached to printhead 3 so that
printhead 3 moves with secondary platform 31.
Referring to FIG. 2, a lead screw 33 extends between first and
second posts 35,37 and is rotatably mounted within each post 35,37.
End portion 33a of lead screw 33 has a pulley 39 fixedly mounted
thereto. Pulley 39 is operatively connected via timing belt 41 to
pulley 43 which is fixedly mounted to and driven into rotation by
shaft 45 of motor 47. Motor 47 is supported on base 48 and is
electrically connected to a controller (i.e. microprocessor) 49 of
the mail handling apparatus 1 so that when controller 49 energizes
motor 47 in a conventional manner, the drive train of shaft 45,
pulley 43, belt 41, and pulley 39 forces the lead screw 33 into
rotation. Motor 47 is rotatable in two directions such that lead
screw 33 can also be rotated in two directions.
Main platform 25 has a bore 25a extending therethrough which has
screw threads corresponding to the threads on lead screw 33. Lead
screw 33 passes through bore 25a in main platform 25 such that the
threads of lead screw 33 and the threads of bore 25a intermesh.
Thus, when lead screw 33 is forced into rotation by motor 47, main
platform 25 is forced to move along lead screw 33 between the
mailpiece printing position of FIG. 1 and the maintenance position
of printhead 3 shown in FIGS. 3 and 4. Controller 49 is capable of
deenergizing motor 47 as required in order to stop the printhead at
any intermediate position between the mailpiece printing position
and the maintenance position.
A guide rod 50 extends between and is fixedly mounted within third
and forth posts 51,53. Guide rod 50 passes through a second bore
25b in main platform 25 such that main platform 25 is free to slide
along guide rod 50 as it is forced to move between the mailpiece
print position and the maintenance position. Guide rod 50 assists
in stabilizing main platform 25 such that nozzles 17 are presented
relative to the mailpiece 5 and the tape 21 at a predetermined
orientation.
A rack gear 55 is mounted via supporting structure 56 to the mail
handling apparatus housing at a position such that the teeth 29a of
gear segment 29 intermesh with the teeth 55a of rack gear 55 during
a portion of the movement of printhead 3 between the mailpiece
printing position and the maintenance position. As rack gear teeth
55a intermesh with gear segment teeth 29a, shaft 27 is forced to
rotate causing a corresponding rotation of secondary platform 31
and printhead 3 as will be discussed in more detail below.
Main platform 25 has a pair of projecting surfaces 57,59 each
having a respective detent 61,63 therein. Secondary platform 31 has
a spring loaded pin 65 extending therefrom which projects into one
of the two detents 61,63 depending upon the position of the
printhead 3, to secure the printhead 3 in position as discussed in
more detail below. Additionally, main platform 25 has a lever arm
67 pivotally mounted thereto which is biased away from projecting
surface 57 by a leaf spring 69 which projects through arm 67 and
which is also mounted to a projecting portion 70 of main platform
25. Arm 67 remains in this position until during movement of main
platform 25, it interferes with a projection 71 which is suspended
from a rear column 75 of the mail handling apparatus 1. When
carriage assembly 23 moves toward the maintenance position
projection 71 initially contacts and rides along a front surface
67a of arm 67 ultimately forcing arm 67 into the position of FIG. 4
to help retain pin 65 in detent 61.
The operation if the inventive apparatus will be described in
detail herein below. Assuming that printhead 3 is in the mailpiece
printing position of FIG. 1 and printing has been completed,
controller 49 energizes motor 47 to rotate shaft 45 in a direction
that causes a corresponding rotation of lead screw 33 through the
drive system of shaft 45, pulley 43, belt 41, and pulley 39. Lead
screw 33 interacts with the threads in bore 25a forcing carriage
assembly 23 to move toward the tape printing position of FIG. 1.
Controller 49 can cause motor 47 to be deenergized at any position
between the mailpiece printing position and the maintenance
position of FIGS. 3 and 4, such as for example, at the tape
printing station if printing on tape 21 is required. However,
assuming that no tape printing is to occur, motor 47 will continue
to operate to move carriage assembly 23 toward the maintenance
position. Prior to reaching the maintenance position, gear segment
teeth 29a intermesh with rack gear teeth 55a. As carriage assembly
23 continues to move toward the maintenance position, the
interaction of gear segment teeth 29a and rack gear teeth 55a
causes shaft 27 and, in turn, secondary platform 31 and printhead 3
to rotate (counterclockwise as viewed in FIG. 1) until the
printhead 3 has rotated 90 degrees relative to its orientation in
FIG. 1. At this point of rotation, gear segment 29 has moved to a
position beyond rack gear 55 such that no further rotation of
printhead 3 occurs and it is retained in its 90 degree detent
position. Motor 47 remains energized until carriage 23 has moved to
the maintenance position such that printhead 3 is aligned with a
conventional maintenance station 81 mounted on a support structure
83 connected to the mail handling apparatus frame. As previously
discussed, maintenance stations are well known in the art and can
include a purge capability, a vacuum capability, a wiper for wiping
contamination from the nozzles 17 and a cover which covers and
seals the printhead nozzles 17 when the printhead 3 is in the
maintenance position.
Referring to FIG. 4, it is important to note that since the nozzles
17 are located in a row transverse to the flow of mail, if a wiper
associated with the maintenance station 81 were simply disposed in
line with the movement of the printhead 3 back toward the
maintenance station 81, the wiper would be wiping along the row of
nozzles 17. This is an unacceptable way of wiping the nozzles 17
since if their is contamination on the first nozzle being wiped,
the contamination could be spread into the remaining nozzles 17 as
the nozzles 17 pass over the wiper. Accordingly, it is desirable
that the wiper passes over the printhead nozzles 17 either
transverse to the nozzle 17 row direction or at least an angle
relative thereto. By positioning the maintenance station 81 lateral
to the movement of carriage 23 and rotating the printhead 90
degrees prior to entering the maintenance station 81, the wiper
blade 87 of the maintenance station 81 is positioned parallel to
the row of nozzles 17 such that as the fully rotated printhead 3 is
moved back into the maintenance station 81, wiper 85 passes across
nozzles 17 transverse to the direction of the nozzle 17 row. While
wiper 85 is shown as being part of the maintenance station 81, it
could easily be positioned separate therefrom such that it would
interact with the row of nozzles 17 during part of the actual 90
degree rotation of printhead 3.
A further feature of the invention, discussed briefly above,
concerns projecting surfaces 57,59 and spring loaded pin 65. When
printhead 3 is positioned as shown in FIG. 1, arm 67 is biased away
from projection 57 and spring loaded pin 65 resides in detent 63
thereby holding printhead 3 in the orientation required for
printing. As printhead 3 is rotated 90 degrees while moving toward
the maintenance position, spring loaded pin 65 moves out of detent
63 and rotates in the counterclockwise direction with secondary
platform 31. When platform 31 has rotated 90 degrees, pin 65 has
now rotated into detent 61 to secure printhead 3 in the 90 degree
position for subsequent engagement with the maintenance station 81.
As the rotated printhead 3 continues to move toward the maintenance
position, arm 67 contacts projection 71 and is forced to move
against the biasing force of leaf spring 69 until it contacts
spring loaded pin 65, further securing spring loaded pin 65 in
detent 61. Arm 67 is needed to ensure that spring loaded pin 65 is
not dislodged from detent 61 when wiper 85 contacts nozzles 17 and
a cover (not shown) of maintenance station 81 is actuated in a
known manner to cap and seal printhead 3.
It will be apparent to one possessing ordinary skill in the art
that the movements of the printhead 3, carriage assembly 23, lever
arm 67 and spring biased pin 65 are directly opposite to the
movements set forth above as the carriage 23 moves from the
maintenance position back to the printing position.
Additional advantages and modifications will readily occur to those
skilled in the art. Therefore, the invention in its broader aspects
is not limited to the specific details, and representative devices,
shown and described herein. Accordingly, various modifications may
be made without departing from the spirit or scope of the general
inventive concept as defined by the appended claims.
* * * * *